Fix for #1902 is merged from trunk

cmake/OpenCVIOLibs.cmake

@@ -9,7 +9,11 @@ if(BUILD_ZLIB)
   unset_all(ZLIB_FOUND)
 else()
   include(FindZLIB)
-  if(ZLIB_FOUND AND NOT ZLIB_VERSION_STRING)
+  if(ZLIB_FOUND)
+    if(ZLIB_VERSION_STRING)
+      #cmake 2.8.2 bug - it fails to determine zlib version
+      unset(ZLIB_VERSION_STRING CACHE)
+    endif()
     ocv_parse_header2(ZLIB "${ZLIB_INCLUDE_DIR}/zlib.h" ZLIB_VERSION "")
   endif()
   if(ZLIB_FOUND AND ANDROID)